JEE Main · 2024 · 01 Feb 2024 · Shift 2 · Units & Measurement

Significant figures are counted starting from the first non-zero digit. In 1001, all four digits are significant, giving 4 significant figures. In 010.1, the leading zero before the decimal carries no significance, leaving 3 significant figures (1, 0, 1). In 100.100, the presence of a decimal point makes every digit from the first non-zero digit onward significant, including the trailing zeros, giving 6 significant figures. In 0.0010010, the zeros before the first non-zero digit are not counted, but the internal and trailing zeros after it are, leaving 5 significant figures (1, 0, 0, 1, 0). So (A) matches (II) with 4, (B) matches (I) with 3, (C) matches (IV) with 6, and (D) matches (III) with 5.